1. Technical Field
The present disclosure is directed to a system and process of generating an ultrasound image and, more particularly, to optimizing the reconstruction of an image for the amount of relative motion between the media and the transducer by adjusting the period of time over which acquisition data can be utilized to improve the quality of the reconstruction.
2. Description of the Related Art
Conventional ultrasound imaging systems use different acquisition methods to trade off image quality and time-motion resolution. For example, if motion in the media is low, and the ultrasound sonographer can keep a hand-held probe's motion to a minimum, acquisition and image reconstruction methods that combine multiple data sets can be used to implement features such as multiple transmit zone focusing, frequency compounding and spatial compounding—features that enhance image quality by providing improved spatial resolution and contrast detail. When the operator is moving the transducer rapidly, or there is motion in the media, which for medical applications could be due to breathing or cardiovascular pulsations, these image enhancement features are not effective, due to signal phase changes and image registration problems over the longer acquisition periods. Since these acquisition and reconstruction methods operate over the entire image space, the sonographer must choose a method suited to the amount of media motion in the diagnostic application prior to performing the scanning procedure. This limits the best ultrasound image quality to those applications with a minimal amount of media motion and for which the operator has properly chosen the correct scanning method.
In addition to the acquisition and reconstruction methods for image quality improvement mentioned above, there are also synthetic aperture techniques where multiple receive apertures are combined to produce a better image reconstruction. An example of this approach is an ‘ideal’ reconstruction, where a transmit is performed on each individual transducer element in the aperture while receiving on all elements. Combining the data from all of these transmit/receive acquisitions allows an image reconstruction that is in perfect focus at all points, both for transmit and receive. While the ideal reconstruction provides the best possible image resolution from a given transducer, it is almost never used in conventional ultrasound imaging systems. This is due to the long acquisition times for each image frame, during which the phase information in the returning ultrasound echoes must remain nearly stationary, so that multiple acquisitions can be combined. Any motion of the transducer or media during the acquisition phase will change the phase information and degrade the image reconstruction.